1 |
|
|
/* $OpenBSD: rthread_sem.c,v 1.26 2017/09/05 02:40:54 guenther Exp $ */ |
2 |
|
|
/* |
3 |
|
|
* Copyright (c) 2004,2005,2013 Ted Unangst <tedu@openbsd.org> |
4 |
|
|
* All Rights Reserved. |
5 |
|
|
* |
6 |
|
|
* Permission to use, copy, modify, and distribute this software for any |
7 |
|
|
* purpose with or without fee is hereby granted, provided that the above |
8 |
|
|
* copyright notice and this permission notice appear in all copies. |
9 |
|
|
* |
10 |
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
11 |
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
12 |
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
13 |
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
14 |
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
15 |
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
16 |
|
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
17 |
|
|
*/ |
18 |
|
|
|
19 |
|
|
#include <sys/types.h> |
20 |
|
|
#include <sys/mman.h> |
21 |
|
|
#include <sys/stat.h> |
22 |
|
|
|
23 |
|
|
#include <errno.h> |
24 |
|
|
#include <fcntl.h> |
25 |
|
|
#include <sha2.h> |
26 |
|
|
#include <stdarg.h> |
27 |
|
|
#include <stdlib.h> |
28 |
|
|
#include <stdio.h> |
29 |
|
|
#include <string.h> |
30 |
|
|
#include <unistd.h> |
31 |
|
|
|
32 |
|
|
#include <pthread.h> |
33 |
|
|
|
34 |
|
|
#include "rthread.h" |
35 |
|
|
#include "cancel.h" /* in libc/include */ |
36 |
|
|
|
37 |
|
|
#define SHARED_IDENT ((void *)-1) |
38 |
|
|
|
39 |
|
|
/* SHA256_DIGEST_STRING_LENGTH includes nul */ |
40 |
|
|
/* "/tmp/" + sha256 + ".sem" */ |
41 |
|
|
#define SEM_PATH_SIZE (5 + SHA256_DIGEST_STRING_LENGTH + 4) |
42 |
|
|
|
43 |
|
|
/* long enough to be hard to guess */ |
44 |
|
|
#define SEM_RANDOM_NAME_LEN 10 |
45 |
|
|
|
46 |
|
|
/* |
47 |
|
|
* Size of memory to be mmap()'ed by named semaphores. |
48 |
|
|
* Should be >= SEM_PATH_SIZE and page-aligned. |
49 |
|
|
*/ |
50 |
|
|
#define SEM_MMAP_SIZE _thread_pagesize |
51 |
|
|
|
52 |
|
|
/* |
53 |
|
|
* Internal implementation of semaphores |
54 |
|
|
*/ |
55 |
|
|
int |
56 |
|
|
_sem_wait(sem_t sem, int tryonly, const struct timespec *abstime, |
57 |
|
|
int *delayed_cancel) |
58 |
|
|
{ |
59 |
|
264668 |
void *ident = (void *)&sem->waitcount; |
60 |
|
|
int r; |
61 |
|
|
|
62 |
✗✓ |
132334 |
if (sem->shared) |
63 |
|
|
ident = SHARED_IDENT; |
64 |
|
|
|
65 |
|
132334 |
_spinlock(&sem->lock); |
66 |
✓✓ |
132334 |
if (sem->value) { |
67 |
|
131185 |
sem->value--; |
68 |
|
|
r = 0; |
69 |
✓✓ |
132334 |
} else if (tryonly) { |
70 |
|
|
r = EAGAIN; |
71 |
|
355 |
} else { |
72 |
|
794 |
sem->waitcount++; |
73 |
|
794 |
do { |
74 |
|
806 |
r = __thrsleep(ident, CLOCK_REALTIME, abstime, |
75 |
|
806 |
&sem->lock, delayed_cancel); |
76 |
|
806 |
_spinlock(&sem->lock); |
77 |
|
|
/* ignore interruptions other than cancelation */ |
78 |
✓✓✓✗ ✓✗ |
830 |
if (r == EINTR && (delayed_cancel == NULL || |
79 |
|
12 |
*delayed_cancel == 0)) |
80 |
|
12 |
r = 0; |
81 |
✓✓✓✓
|
1608 |
} while (r == 0 && sem->value == 0); |
82 |
|
794 |
sem->waitcount--; |
83 |
✓✓ |
794 |
if (r == 0) |
84 |
|
790 |
sem->value--; |
85 |
|
|
} |
86 |
|
132334 |
_spinunlock(&sem->lock); |
87 |
|
132334 |
return (r); |
88 |
|
|
} |
89 |
|
|
|
90 |
|
|
/* always increment count */ |
91 |
|
|
int |
92 |
|
|
_sem_post(sem_t sem) |
93 |
|
|
{ |
94 |
|
269038 |
void *ident = (void *)&sem->waitcount; |
95 |
|
|
int rv = 0; |
96 |
|
|
|
97 |
✗✓ |
134519 |
if (sem->shared) |
98 |
|
|
ident = SHARED_IDENT; |
99 |
|
|
|
100 |
|
134519 |
_spinlock(&sem->lock); |
101 |
|
134519 |
sem->value++; |
102 |
✓✓ |
134519 |
if (sem->waitcount) { |
103 |
|
799 |
__thrwakeup(ident, 1); |
104 |
|
|
rv = 1; |
105 |
|
799 |
} |
106 |
|
134519 |
_spinunlock(&sem->lock); |
107 |
|
134519 |
return (rv); |
108 |
|
|
} |
109 |
|
|
|
110 |
|
|
/* |
111 |
|
|
* exported semaphores |
112 |
|
|
*/ |
113 |
|
|
int |
114 |
|
|
sem_init(sem_t *semp, int pshared, unsigned int value) |
115 |
|
|
{ |
116 |
|
|
sem_t sem; |
117 |
|
|
|
118 |
✗✓ |
21898 |
if (value > SEM_VALUE_MAX) { |
119 |
|
|
errno = EINVAL; |
120 |
|
|
return (-1); |
121 |
|
|
} |
122 |
|
|
|
123 |
✗✓ |
10949 |
if (pshared) { |
124 |
|
|
errno = EPERM; |
125 |
|
|
return (-1); |
126 |
|
|
#ifdef notyet |
127 |
|
|
char name[SEM_RANDOM_NAME_LEN]; |
128 |
|
|
sem_t *sempshared; |
129 |
|
|
int i; |
130 |
|
|
|
131 |
|
|
for (;;) { |
132 |
|
|
for (i = 0; i < SEM_RANDOM_NAME_LEN - 1; i++) |
133 |
|
|
name[i] = arc4random_uniform(255) + 1; |
134 |
|
|
name[SEM_RANDOM_NAME_LEN - 1] = '\0'; |
135 |
|
|
sempshared = sem_open(name, O_CREAT | O_EXCL, 0, value); |
136 |
|
|
if (sempshared != SEM_FAILED) |
137 |
|
|
break; |
138 |
|
|
if (errno == EEXIST) |
139 |
|
|
continue; |
140 |
|
|
if (errno != EPERM) |
141 |
|
|
errno = ENOSPC; |
142 |
|
|
return (-1); |
143 |
|
|
} |
144 |
|
|
|
145 |
|
|
/* unnamed semaphore should not be opened twice */ |
146 |
|
|
if (sem_unlink(name) == -1) { |
147 |
|
|
sem_close(sempshared); |
148 |
|
|
errno = ENOSPC; |
149 |
|
|
return (-1); |
150 |
|
|
} |
151 |
|
|
|
152 |
|
|
*semp = *sempshared; |
153 |
|
|
free(sempshared); |
154 |
|
|
return (0); |
155 |
|
|
#endif |
156 |
|
|
} |
157 |
|
|
|
158 |
|
10949 |
sem = calloc(1, sizeof(*sem)); |
159 |
✗✓ |
10949 |
if (!sem) { |
160 |
|
|
errno = ENOSPC; |
161 |
|
|
return (-1); |
162 |
|
|
} |
163 |
|
10949 |
sem->lock = _SPINLOCK_UNLOCKED; |
164 |
|
10949 |
sem->value = value; |
165 |
|
10949 |
*semp = sem; |
166 |
|
|
|
167 |
|
10949 |
return (0); |
168 |
|
10949 |
} |
169 |
|
|
|
170 |
|
|
int |
171 |
|
|
sem_destroy(sem_t *semp) |
172 |
|
|
{ |
173 |
|
|
sem_t sem; |
174 |
|
|
|
175 |
✓✓ |
222 |
if (!_threads_ready) /* for SEM_MMAP_SIZE */ |
176 |
|
8 |
_rthread_init(); |
177 |
|
|
|
178 |
✓✗✗✓
|
222 |
if (!semp || !(sem = *semp)) { |
179 |
|
|
errno = EINVAL; |
180 |
|
|
return (-1); |
181 |
|
|
} |
182 |
|
|
|
183 |
✓✓ |
111 |
if (sem->waitcount) { |
184 |
|
|
#define MSG "sem_destroy on semaphore with waiters!\n" |
185 |
|
8 |
write(2, MSG, sizeof(MSG) - 1); |
186 |
|
|
#undef MSG |
187 |
|
8 |
errno = EBUSY; |
188 |
|
8 |
return (-1); |
189 |
|
|
} |
190 |
|
|
|
191 |
|
103 |
*semp = NULL; |
192 |
✗✓ |
103 |
if (sem->shared) |
193 |
|
|
munmap(sem, SEM_MMAP_SIZE); |
194 |
|
|
else |
195 |
|
103 |
free(sem); |
196 |
|
|
|
197 |
|
103 |
return (0); |
198 |
|
111 |
} |
199 |
|
|
|
200 |
|
|
int |
201 |
|
|
sem_getvalue(sem_t *semp, int *sval) |
202 |
|
|
{ |
203 |
|
|
sem_t sem; |
204 |
|
|
|
205 |
✓✗✗✓
|
84 |
if (!semp || !(sem = *semp)) { |
206 |
|
|
errno = EINVAL; |
207 |
|
|
return (-1); |
208 |
|
|
} |
209 |
|
|
|
210 |
|
28 |
_spinlock(&sem->lock); |
211 |
|
28 |
*sval = sem->value; |
212 |
|
28 |
_spinunlock(&sem->lock); |
213 |
|
|
|
214 |
|
28 |
return (0); |
215 |
|
28 |
} |
216 |
|
|
|
217 |
|
|
int |
218 |
|
|
sem_post(sem_t *semp) |
219 |
|
|
{ |
220 |
|
|
sem_t sem; |
221 |
|
|
|
222 |
✓✗✗✓
|
371079 |
if (!semp || !(sem = *semp)) { |
223 |
|
|
errno = EINVAL; |
224 |
|
|
return (-1); |
225 |
|
|
} |
226 |
|
|
|
227 |
|
123693 |
_sem_post(sem); |
228 |
|
|
|
229 |
|
123693 |
return (0); |
230 |
|
123693 |
} |
231 |
|
|
|
232 |
|
|
int |
233 |
|
|
sem_wait(sem_t *semp) |
234 |
|
|
{ |
235 |
|
85394 |
struct tib *tib = TIB_GET(); |
236 |
|
|
pthread_t self; |
237 |
|
|
sem_t sem; |
238 |
|
|
int r; |
239 |
|
42697 |
PREP_CANCEL_POINT(tib); |
240 |
|
|
|
241 |
✓✓ |
42697 |
if (!_threads_ready) |
242 |
|
2615 |
_rthread_init(); |
243 |
|
42697 |
self = tib->tib_thread; |
244 |
|
|
|
245 |
✓✗✓✓
|
85394 |
if (!semp || !(sem = *semp)) { |
246 |
|
4 |
errno = EINVAL; |
247 |
|
4 |
return (-1); |
248 |
|
|
} |
249 |
|
|
|
250 |
✓✗✗✓
|
85386 |
ENTER_DELAYED_CANCEL_POINT(tib, self); |
251 |
|
42693 |
r = _sem_wait(sem, 0, NULL, &self->delayed_cancel); |
252 |
✓✗✗✓ ✗✗ |
85386 |
LEAVE_CANCEL_POINT_INNER(tib, r); |
253 |
|
|
|
254 |
✗✓ |
42693 |
if (r) { |
255 |
|
|
errno = r; |
256 |
|
|
return (-1); |
257 |
|
|
} |
258 |
|
|
|
259 |
|
42693 |
return (0); |
260 |
|
42697 |
} |
261 |
|
|
|
262 |
|
|
int |
263 |
|
|
sem_timedwait(sem_t *semp, const struct timespec *abstime) |
264 |
|
|
{ |
265 |
|
32 |
struct tib *tib = TIB_GET(); |
266 |
|
|
pthread_t self; |
267 |
|
|
sem_t sem; |
268 |
|
|
int r; |
269 |
|
16 |
PREP_CANCEL_POINT(tib); |
270 |
|
|
|
271 |
✓✓ |
16 |
if (!_threads_ready) |
272 |
|
4 |
_rthread_init(); |
273 |
|
16 |
self = tib->tib_thread; |
274 |
|
|
|
275 |
✓✗✓✓
|
32 |
if (!semp || !(sem = *semp)) { |
276 |
|
4 |
errno = EINVAL; |
277 |
|
4 |
return (-1); |
278 |
|
|
} |
279 |
|
|
|
280 |
✓✗✗✓
|
24 |
ENTER_DELAYED_CANCEL_POINT(tib, self); |
281 |
|
12 |
r = _sem_wait(sem, 0, abstime, &self->delayed_cancel); |
282 |
✓✗✓✓ ✗✓ |
28 |
LEAVE_CANCEL_POINT_INNER(tib, r); |
283 |
|
|
|
284 |
✓✓ |
12 |
if (r) { |
285 |
|
4 |
errno = r == EWOULDBLOCK ? ETIMEDOUT : r; |
286 |
|
4 |
return (-1); |
287 |
|
|
} |
288 |
|
|
|
289 |
|
8 |
return (0); |
290 |
|
16 |
} |
291 |
|
|
|
292 |
|
|
int |
293 |
|
|
sem_trywait(sem_t *semp) |
294 |
|
|
{ |
295 |
|
|
sem_t sem; |
296 |
|
|
int r; |
297 |
|
|
|
298 |
✓✗✓✓
|
244068 |
if (!semp || !(sem = *semp)) { |
299 |
|
4 |
errno = EINVAL; |
300 |
|
4 |
return (-1); |
301 |
|
|
} |
302 |
|
|
|
303 |
|
81352 |
r = _sem_wait(sem, 1, NULL, NULL); |
304 |
|
|
|
305 |
✓✓ |
81352 |
if (r) { |
306 |
|
355 |
errno = r; |
307 |
|
355 |
return (-1); |
308 |
|
|
} |
309 |
|
|
|
310 |
|
80997 |
return (0); |
311 |
|
81356 |
} |
312 |
|
|
|
313 |
|
|
|
314 |
|
|
static void |
315 |
|
|
makesempath(const char *origpath, char *sempath, size_t len) |
316 |
|
|
{ |
317 |
|
|
char buf[SHA256_DIGEST_STRING_LENGTH]; |
318 |
|
|
|
319 |
|
|
SHA256Data(origpath, strlen(origpath), buf); |
320 |
|
|
snprintf(sempath, len, "/tmp/%s.sem", buf); |
321 |
|
|
} |
322 |
|
|
|
323 |
|
|
sem_t * |
324 |
|
|
sem_open(const char *name, int oflag, ...) |
325 |
|
|
{ |
326 |
|
|
char sempath[SEM_PATH_SIZE]; |
327 |
|
|
struct stat sb; |
328 |
|
|
sem_t sem, *semp; |
329 |
|
|
unsigned int value = 0; |
330 |
|
|
int created = 0, fd; |
331 |
|
|
|
332 |
|
|
if (!_threads_ready) |
333 |
|
|
_rthread_init(); |
334 |
|
|
|
335 |
|
|
if (oflag & ~(O_CREAT | O_EXCL)) { |
336 |
|
|
errno = EINVAL; |
337 |
|
|
return (SEM_FAILED); |
338 |
|
|
} |
339 |
|
|
|
340 |
|
|
if (oflag & O_CREAT) { |
341 |
|
|
va_list ap; |
342 |
|
|
va_start(ap, oflag); |
343 |
|
|
/* 3rd parameter mode is not used */ |
344 |
|
|
va_arg(ap, mode_t); |
345 |
|
|
value = va_arg(ap, unsigned); |
346 |
|
|
va_end(ap); |
347 |
|
|
|
348 |
|
|
if (value > SEM_VALUE_MAX) { |
349 |
|
|
errno = EINVAL; |
350 |
|
|
return (SEM_FAILED); |
351 |
|
|
} |
352 |
|
|
} |
353 |
|
|
|
354 |
|
|
makesempath(name, sempath, sizeof(sempath)); |
355 |
|
|
fd = open(sempath, O_RDWR | O_NOFOLLOW | oflag, 0600); |
356 |
|
|
if (fd == -1) |
357 |
|
|
return (SEM_FAILED); |
358 |
|
|
if (fstat(fd, &sb) == -1 || !S_ISREG(sb.st_mode)) { |
359 |
|
|
close(fd); |
360 |
|
|
errno = EINVAL; |
361 |
|
|
return (SEM_FAILED); |
362 |
|
|
} |
363 |
|
|
if (sb.st_uid != geteuid()) { |
364 |
|
|
close(fd); |
365 |
|
|
errno = EPERM; |
366 |
|
|
return (SEM_FAILED); |
367 |
|
|
} |
368 |
|
|
if (sb.st_size != (off_t)SEM_MMAP_SIZE) { |
369 |
|
|
if (!(oflag & O_CREAT)) { |
370 |
|
|
close(fd); |
371 |
|
|
errno = EINVAL; |
372 |
|
|
return (SEM_FAILED); |
373 |
|
|
} |
374 |
|
|
if (sb.st_size != 0) { |
375 |
|
|
close(fd); |
376 |
|
|
errno = EINVAL; |
377 |
|
|
return (SEM_FAILED); |
378 |
|
|
} |
379 |
|
|
if (ftruncate(fd, SEM_MMAP_SIZE) == -1) { |
380 |
|
|
close(fd); |
381 |
|
|
errno = EINVAL; |
382 |
|
|
return (SEM_FAILED); |
383 |
|
|
} |
384 |
|
|
|
385 |
|
|
created = 1; |
386 |
|
|
} |
387 |
|
|
sem = mmap(NULL, SEM_MMAP_SIZE, PROT_READ | PROT_WRITE, |
388 |
|
|
MAP_SHARED, fd, 0); |
389 |
|
|
close(fd); |
390 |
|
|
if (sem == MAP_FAILED) { |
391 |
|
|
errno = EINVAL; |
392 |
|
|
return (SEM_FAILED); |
393 |
|
|
} |
394 |
|
|
semp = malloc(sizeof(*semp)); |
395 |
|
|
if (!semp) { |
396 |
|
|
munmap(sem, SEM_MMAP_SIZE); |
397 |
|
|
errno = ENOSPC; |
398 |
|
|
return (SEM_FAILED); |
399 |
|
|
} |
400 |
|
|
if (created) { |
401 |
|
|
sem->lock = _SPINLOCK_UNLOCKED; |
402 |
|
|
sem->value = value; |
403 |
|
|
sem->shared = 1; |
404 |
|
|
} |
405 |
|
|
*semp = sem; |
406 |
|
|
|
407 |
|
|
return (semp); |
408 |
|
|
} |
409 |
|
|
|
410 |
|
|
int |
411 |
|
|
sem_close(sem_t *semp) |
412 |
|
|
{ |
413 |
|
|
sem_t sem; |
414 |
|
|
|
415 |
|
|
if (!semp || !(sem = *semp) || !sem->shared) { |
416 |
|
|
errno = EINVAL; |
417 |
|
|
return (-1); |
418 |
|
|
} |
419 |
|
|
|
420 |
|
|
*semp = NULL; |
421 |
|
|
munmap(sem, SEM_MMAP_SIZE); |
422 |
|
|
free(semp); |
423 |
|
|
|
424 |
|
|
return (0); |
425 |
|
|
} |
426 |
|
|
|
427 |
|
|
int |
428 |
|
|
sem_unlink(const char *name) |
429 |
|
|
{ |
430 |
|
|
char sempath[SEM_PATH_SIZE]; |
431 |
|
|
|
432 |
|
|
makesempath(name, sempath, sizeof(sempath)); |
433 |
|
|
return (unlink(sempath)); |
434 |
|
|
} |